Some bottled spring water have blue caps.
The caps look the pretty much the same no matter how they are stacked. Opening to opening or opening to top.
Quarters fit inside the caps.
You'll need two. One is the lid and the other the box.

If you know some Okito Box moves and have two caps then you're ready for some impromptu magic. Give it a shot.
Enjoy,

Allmagic.com has an effect there at the moment (March 2007) that could work using a beer bottle cap. It is called Coin Box Slider.
Three coins in the hand, they are placed in the cap/coin box, one coin passes through the cap/coin box and the hand on which it is placed and falls to the table.